3D graphics eBook - Course Materials Repository
3D graphics eBook - Course Materials Repository 3D graphics eBook - Course Materials Repository
Geometry processing 47 Geometry processing Geometry processing, or mesh processing, is a fast-growing area of research that uses concepts from applied mathematics, computer science and engineering to design efficient algorithms for the acquisition, reconstruction, analysis, manipulation, simulation and transmission of complex 3D models. Applications of geometry processing algorithms already cover a wide range of areas from multimedia, entertainment and classical computer-aided design, to biomedical computing, reverse engineering and scientific computing. External links • Siggraph 2001 Course on Digital Geometry Processing [1] , by Peter Schroder and Wim Sweldens • Symposium on Geometry Processing [2] • Multi-Res Modeling Group [3] , Caltech • Mathematical Geometry Processing Group [4] , Free University of Berlin References [1] http:/ / www. multires. caltech. edu/ pubs/ DGPCourse/ [2] http:/ / www. geometryprocessing. org/ [3] http:/ / www. multires. caltech. edu/ [4] http:/ / geom. mi. fu-berlin. de/ index. html Global illumination Rendering without global illumination. Areas that lie outside of the ceiling lamp's direct light lack definition. For example, the lamp's housing appears completely uniform. Without the ambient light added into the render, it would appear uniformly black.
Global illumination 48 Rendering with global illumination. Light is reflected by surfaces, and colored light transfers from one surface to another. Notice how color from the red wall and green wall (not visible) reflects onto other surfaces in the scene. Also notable is the caustic projected onto the red wall from light passing through the glass sphere. Global illumination is a general name for a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes. Such algorithms take into account not only the light which comes directly from a light source (direct illumination), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene, whether reflective or not (indirect illumination). Theoretically reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another object (as opposed to an object being affected only by a direct light). In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination. Images rendered using global illumination algorithms often appear more photorealistic than images rendered using only direct illumination algorithms. However, such images are computationally more expensive and consequently much slower to generate. One common approach is to compute the global illumination of a scene and store that information with the geometry, i.e., radiosity. That stored data can then be used to generate images from different viewpoints for generating walkthroughs of a scene without having to go through expensive lighting calculations repeatedly. Radiosity, ray tracing, beam tracing, cone tracing, path tracing, Metropolis light transport, ambient occlusion, photon mapping, and image based lighting are examples of algorithms used in global illumination, some of which may be used together to yield results that are not fast, but accurate. These algorithms model diffuse inter-reflection which is a very important part of global illumination; however most of these (excluding radiosity) also model specular reflection, which makes them more accurate algorithms to solve the lighting equation and provide a more realistically illuminated scene. The algorithms used to calculate the distribution of light energy between surfaces of a scene are closely related to heat transfer simulations performed using finite-element methods in engineering design. In real-time 3D graphics, the diffuse inter-reflection component of global illumination is sometimes approximated by an "ambient" term in the lighting equation, which is also called "ambient lighting" or "ambient color" in 3D software packages. Though this method of approximation (also known as a "cheat" because it's not really a global illumination method) is easy to perform computationally, when used alone it does not provide an adequately realistic effect. Ambient lighting is known to "flatten" shadows in 3D scenes, making the overall visual effect more bland. However, used properly, ambient lighting can be an efficient way to make up for a lack of processing power.
- Page 1 and 2: 3D Rendering PDF generated using th
- Page 3 and 4: Image-based lighting 64 Image plane
- Page 5 and 6: References Article Sources and Cont
- Page 7 and 8: 3D rendering 2 Non real-time Animat
- Page 9 and 10: 3D rendering 4 The shaded three-dim
- Page 11 and 12: Ambient occlusion 6 ambient occlusi
- Page 13 and 14: Ambient occlusion 8 • ShadeVis (h
- Page 15 and 16: Anisotropic filtering 10 will only
- Page 17 and 18: Beam tracing 12 Beam tracing Beam t
- Page 19 and 20: Bilinear filtering 14 Are all true.
- Page 21 and 22: Binary space partitioning 16 togeth
- Page 23 and 24: Binary space partitioning 18 Other
- Page 25 and 26: Binary space partitioning 20 [1] Bi
- Page 27 and 28: Bounding interval hierarchy 22 Prop
- Page 29 and 30: Bounding volume 24 bounding boxes b
- Page 31 and 32: Bump mapping 26 Bump mapping Bump m
- Page 33 and 34: CatmullClark subdivision surface 28
- Page 35 and 36: CatmullClark subdivision surface 30
- Page 37 and 38: Conversion between quaternions and
- Page 39 and 40: Cube mapping 34 Advantages Cube map
- Page 41 and 42: Cube mapping 36 Related A large set
- Page 43 and 44: Diffuse reflection 38 2), or, of co
- Page 45 and 46: Displacement mapping 40 Meaning of
- Page 47 and 48: DooSabin subdivision surface 42 Ext
- Page 49 and 50: False radiosity 44 False radiosity
- Page 51: Geometry pipelines 46 Geometry pipe
- Page 55 and 56: Gouraud shading 50 Gouraud shading
- Page 57 and 58: Graphics pipeline 52 Graphics pipel
- Page 59 and 60: Graphics pipeline 54 References 1.
- Page 61 and 62: Hidden surface determination 56 imp
- Page 63 and 64: High dynamic range rendering 58 Hig
- Page 65 and 66: High dynamic range rendering 60 Ton
- Page 67 and 68: High dynamic range rendering 62 Fro
- Page 69 and 70: High dynamic range rendering 64 •
- Page 71 and 72: Irregular Z-buffer 66 Applications
- Page 73 and 74: Lambert's cosine law 68 than would
- Page 75 and 76: Lambertian reflectance 70 Lambertia
- Page 77 and 78: Level of detail 72 Well known appro
- Page 79 and 80: Level of detail 74 Hierarchical LOD
- Page 81 and 82: Newell's algorithm 76 Newell's algo
- Page 83 and 84: Non-uniform rational B-spline 78 Us
- Page 85 and 86: Non-uniform rational B-spline 80 of
- Page 87 and 88: Non-uniform rational B-spline 82 ar
- Page 89 and 90: Non-uniform rational B-spline 84 Ex
- Page 91 and 92: Normal mapping 86 How it works To c
- Page 93 and 94: OrenNayar reflectance model 88 Oren
- Page 95 and 96: OrenNayar reflectance model 90 , ,
- Page 97 and 98: Painter's algorithm 92 The algorith
- Page 99 and 100: Parallax mapping 94 • Parallax Ma
- Page 101 and 102: Particle system 96 A cube emitting
Geometry processing 47<br />
Geometry processing<br />
Geometry processing, or mesh processing, is a fast-growing area of research that uses concepts from applied<br />
mathematics, computer science and engineering to design efficient algorithms for the acquisition, reconstruction,<br />
analysis, manipulation, simulation and transmission of complex <strong>3D</strong> models. Applications of geometry processing<br />
algorithms already cover a wide range of areas from multimedia, entertainment and classical computer-aided design,<br />
to biomedical computing, reverse engineering and scientific computing.<br />
External links<br />
• Siggraph 2001 <strong>Course</strong> on Digital Geometry Processing [1] , by Peter Schroder and Wim Sweldens<br />
• Symposium on Geometry Processing [2]<br />
• Multi-Res Modeling Group [3] , Caltech<br />
• Mathematical Geometry Processing Group [4] , Free University of Berlin<br />
References<br />
[1] http:/ / www. multires. caltech. edu/ pubs/ DGP<strong>Course</strong>/<br />
[2] http:/ / www. geometryprocessing. org/<br />
[3] http:/ / www. multires. caltech. edu/<br />
[4] http:/ / geom. mi. fu-berlin. de/ index. html<br />
Global illumination<br />
Rendering without global illumination. Areas that lie outside of the ceiling lamp's direct light lack definition. For example, the lamp's housing<br />
appears completely uniform. Without the ambient light added into the render, it would appear uniformly black.
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